Oddball .45 Auto Rim -- is this a proof?

I’ve had this .45 Auto Rim kicking around in my “whatthis” box for some time. The case appears to be copper…not discolored from previous corrosion (note no pitting on the case), but either made from copper or copper-plated. It is not magnetic.

I have no idea of the age or history, I don’t even remember where I got it. Could this be a proof round? Most early proof rounds I’ve seen use a blackened case, but those are all either WRA or REM-UMC…I don’t know what Peters proof identification was.

Thanks in advance!

I have 10 different PETERS 45 AUTO-RIM headstamped rounds including brass case ball, nickeled case ball and blackened case proof. But no copper plated case. I am sure it is copper plated and not copper. I doubt if it is proof as Peters was using a blackened case with that headstamp. Before the blackened case proof, they use a tinned case and after it was a nickeled case with magenta or red head.

Is there ANY sign, such as at the base of the rim, of nickel
plating. Brass is normaly plated with copper then nickel. The nickel sticks to copper better. Perhaps this is a reload that someone tumbled to clean up the case and it wore all the nickel plating off. I have some 38 Spl. that happened to, but you can usually see some rements of the nickel in the headstamp, etc.

Could it possibly be a case that was intended to be nickel plated but for whatever reason only made it as far as the copper plating stage in the process.

None that I can see.

Is it a loaded round, or could it be a dummy? I have several 22 RF dummys made by Peters that have copper plated brass cases.

It appears to be loaded; at least, there are no holes in the case.